Microbiological Issues in Papermaking
E-Book, Englisch, 226 Seiten
ISBN: 978-0-12-803426-2
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)
Dr. Pratima Bajpai is currently working as a Consultant in the field of Paper and Pulp. She has over 36 years of experience in research at the National Sugar Institute, University of Saskatchewan, the Universitiy of Western Ontario, in Canada, in addition to the Thapar Research and Industrial Development Centre, in India. She also worked as a visiting professor at the University of Waterloo, Canada and as a visiting researcher at Kyushu University, Fukuoka, Japan. She has been named among the World's Top 2% Scientists by Stanford University in the list published in October 2022. This is the third consecutive year that she has made it into the prestigious list. Dr. Bajpai's main areas of expertise are industrial biotechnology, pulp and paper, and environmental biotechnology. She has contributed immensely to the field of industrial biotechnology and is a recognized expert in the field. Dr. Bajpai has written several advanced level technical books on environmental and biotechnological aspects of pulp and paper which have been published by leading publishers in the USA and Europe. She has also contributed chapters to a number of books and encyclopedia, obtained 11 patents, written several technical reports, and has implemented several processes in Indian Paper mills. Dr. Bajpai is an active member of the American Society of Microbiologists and is a reviewer of many international research journals.
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Glossary
Aerobic bacteria These bacteria require oxygen for respiration. Algae Algae are simple celled plants and (like all plants) contain chlorophyll. This traps energy from the sun and uses that energy to convert nutrients and carbon dioxide (which are dissolved in the water) into growth. Alpha-amylase Amylase that catalyzes the hydrolysis of internal alpha-1,4-bonds in starch molecules and starch breakdown products. Amylase An enzyme that catalyzes the breakdown (hydrolysis) of starch. Names such as alpha amylase or endoamylase, beta-amylase, amyloglucosidase (glucoamylase), etc., refer to enzymes that attack starch or starch break down products in slightly different ways. Anaerobic bacteria These bacteria do not require oxygen for respiration. ATP Adenosine triphosphate, an energy-rich molecule that is important as a source of energy in cells. Bacteria Unicellular, prokaryotic, microscopic, generally heterotrophic organism present in great numbers in soil and in water; largely responsible for decomposition of primary and secondary produced organic matter and for mineralization of its constituent elements, C, N, P, S etc. The bacteria are one of the three domains of life, the other being Archaea and Eukarya (eukaryotes). Bacteriophage A virus that infects bacteria and multiplies within the cells. Usually, a bacteriophage can only infect a limited range of bacterial strains. Bacteriostatic Chemical compound that inhibit the growth of bacteria. Biocide Chemical compounds that kill microorganisms. Bactericides, fungicides, etc., are examples. In the paper industry, they are typically used to control slime. These are of two types: oxidizing and nonoxidizing biocides. Biocorrosion Corrosion processes initiated by or accelerated by the growth of microorganisms at the metal surface. Biodegradation The act of degrading a molecule to one or more smaller molecules by biochemical mechanisms (e.g., enzyme action). Biodispersants Chemical compounds that act as “biopenetrators,” opening the biofilms and allowing the biocides to penetrate the layer of the slime. They can also prevent the formation of nonbiological deposits, which could be a nutrient source for the microorganisms, facilitating the action of biocides. Biofilm A slime-like matrix composed of extracellular polymeric substances within which a consortium of microorganisms flourishes. These biofilms may either grow over surfaces, or occupy voids in a porous medium. Biofouling Any deleterious event in which a definable biological activity causes a deterioration in and engineered or natural process or system. Deleterious effects range from clogging, corrosion, and plugging to gas production and bioaccumulation. Biological oxygen demand (BOD) A measure of the amount of oxygen consumed in biological processes that break down organic matter in water. The greater the BOD, the higher the degree of pollution. Bioluminescence The production of light by living organisms. Biosensor A device, especially an electrochemical device, that detects some biological event (for example, respiration, enzymic activity, binding to an antibody) and converts it into an electrical signal that it reports quantitatively and in real time. Cellulases A family of enzymes that hydrolyze ß-1, 4-glucosidic bonds in native cellulose and derived substrates. Chemical pulp Fibrous material obtained by removal from the raw material of a considerable part of those noncellulosic compounds that can be removed by chemical treatment (cooking, delignification, bleaching). Clogging The generation of a mass that interferes with physical functioning of a porous medium. Clogging can be formed through the maturation of biofilms fouling the media and may become complex in structure. Closed-cycle A mill or industrial plant that has little or no process effluent. Chemical oxygen demand (COD) A measure of the oxygen required to oxidize all compounds in water, both organic and inorganic. COD is more widely used because it is a simple procedure and includes the effects of nonbiodegradable organic matter, which can account for up to half of the material discharged. Colony forming units (cfu) When microorganisms do grow on agar media, they commonly form visible distinguishable structures composed mainly of cellular material, which are called colonies. Each of these colonies is considered to have formed from a single colony forming unit that may be a single cell or a clump of cells. By appropriate mathematical relationships of the dilution of the sample and the area of the agar inoculated, it is possible to predict a population as either cfu/mL (for liquids), cfu/g (for solids), or cfu/cm2 (for surfaces). Culture The act of successfully growing a unique strain or a consortium of microorganisms; (noun) a viable collection of a single strain of microorganisms that has been selectively grown in vitro under controlled (laboratory) conditions. Dispersant These are a class of surfactant chemical used in papermaking systems to reduce deposits of pitch and slime, in deinking systems to disperse the ink particles, and in coating formulations to keep the clay particles in suspension. Dissolved and colloidal substances Usually derived from wood and usually having a negative charge, tending to interfere with retention aids and other papermaking additives. Enzyme A protein that has the ability to direct or catalyze a chemical reaction. Extracellular polymers (EPS) The polysaccharide material produced by microorganisms that surround the microbial cells, which enhances the attachment to surfaces. Fungi A kingdom of life forms that are eukaryotic, mycelial or yeast-like, heterotrophic, lacking in chlorophyll, sexually and/or asexually reproductive, and mostly aerobic. Glycocalyx A general term referring to extracellular polymeric material produced by some bacteria composed of carbohydrates, lipids, and proteins. Iron oxidizing bacteria These bacteria are able to oxidize iron by any means from a reduced form of iron (ferrous form) to an oxidized (ferrous) state. Iron-reducing bacteria These bacteria are able to reduce iron by any means from an oxidized form (ferric) to a reduced (ferrous) state. Iron-related bacteria All of those bacteria that are able to accumulate iron in another form beyond that for basic metabolic functioning. These accumulated iron compounds generally collect within the slime (EPS) around the cells and gradually harden (crystallize) over time. Limiting nutrient A major nutrient that is in short supply and restricts the growth of a biomass. Limitations could also be created by the limiting nutrient distorting the ratios of nutritional elements outside of range that would support growth. Macrofouling An intense and/or widespread form of biofouling. Mechanical pulping Mechanical pulping uses revolving disks to grind wood chips into pulp. Water is added to the process to reduce wood damage resulting from heat and friction. One of the nonfibrous elements that is not removed during mechanical pulping is lignin, an organic material that binds fibers of cellulose together in the wood. It is the presence of lignin that is primarily responsible for low durability and yellowing with age. Mechanical (or groundwood) pulp is inexpensive to produce and generates the highest yield. Microbial induced corrosion Corrosion processes initiated by or accelerated by the growth of microorganisms at the metal surface. Microorganism An organism of microscopic size, including bacteria, fungi, and viruses. Non-oxidizing biocide A non-oxidizing biocide is one that functions by mechanisms other than oxidation, including interference with cell metabolism and structure. Oxidizing biocides Agents capable of oxidizing organic matter (e.g., cell material, enzymes, or proteins that are associated with microbiological populations resulting in death of the microorganisms). The most commonly used oxidizing biocides are based on chlorine or bromine (halogens) that liberate hypochlorous or hypobromous acids on hydrolysis in water. The exception is chlorine dioxide, a gas that does not hydrolyze but that functions in the same way. Pectin A highly hydrophilic polysaccharide built up of monomers of an important component of cell walls. Pectinase Pectinase also known as polygalacturonase is the collective term for a row of enzymes that are able to break down or to transform pectins. Polysaccharides Carbohydrates that hydrolyze to yield more than 10 molecules of a monosaccharide (cellulose and starch are glucose polymers). Planktonic organisms Free-living organisms (that swim or float in the water phase). Plate count Test method for the determination of a microbiological contamination and/or for testing the efficiency...
